1. Field of the Invention
The present invention relates to a robot system including a robot supported by a movable carriage.
2. Description of the Related Art
In the related art, a robot system that is configured to extend a work area of a robot by moving a traveling carriage on which the robot is mounted, is known. For example, a traveling carriage to which a robot is fixed travels along a rail that is laid on the ground, is known. Though the traveling carriages are capable of determining a position with high accuracy, dedicated equipment such as rails for the traveling is required. Further, facilities cannot be easily modified after installation. Due to this, a disadvantage arises in that modifications to production process, production method or the like cannot be easily changed.
Also, a device in which a robot is mounted on a carriage that is able to move in any direction and moved to a work area is known (for example, see Japanese Patent No. 5061965 Japanese Unexamined Patent Publication No. 11-58273). This device has a problem in that the robot is mounted on the carriage and thereby positioning accuracy of the robot is not ensured due to the movement of the carriage. In this device, a positional deviation of the carriage is measured by using a camera or a force sensor. Then, the operation of the robot is offset with respect to the amount that is deviated from a predetermined position. By offsetting a teaching position of the robot by calculation, the robot can correctly perform the work even if the carriage deviates from the predetermined position.
Further, Japanese Patent No. 4820395 discloses a system in which a dual arm robot can adjust a work position by own exertion when the position at which the dual arm robot performs the work is changed. In this system, an adjustment of the position of the carriage is automatically carried out.
Regarding vision sensors, Japanese Unexamined Patent Publication No. 2004-138462A discloses a three-dimensional vision sensor that is capable of measuring a three-dimensional position and orientation of a workplace accurately even when the position and orientation of the workpiece change. Additionally, Japanese Patent No. 2602812B discloses a method in which first mark, second mark, and third mark are imaged by using three vision sensors mounted on a carriage, whereby a three-dimensional position and orientation of the object are measured.